In this study, the learning potentials and barriers when introducing 3D printers in Danish Middle Schools, are investigated. The project group collaborated with Create it REAL and the Municipality of Aalborg. First an exploratory Pilot Study was conducted, to investigate how four Danish Middle schools included 3D printing into their classes. The Pilot Study included data from three sources: Interviews with teachers, observations of learning activities, and questionnaires.The findings from the Pilot Study were used to create a proposal for an approach to learning activities with 3D printers dubbed the Oresmian Coordinate System. This approach was created to encourage: tinkering, learning of 21stcentury skills, and reflective exploration of STEM fields. This approach was tested through a Field Study, and through observations as well as a video review session, indications were found that this approach can support a rich collaborative learning environment, and support the teacher in having reflective discussions withpupils regarding designs and iterations.